EXITE2 Observation of the SIGMA Source GRS 1227+025

Abstract

We report the EXITE2 hard X-ray imaging of the sky around 3C273. A 2h observation on May 8, 1997, shows a $\sim$260 mCrab source detected at $\sim 4\sigma$ in each of two bands (50-70 and 70-93 keV) and located $\sim$30' from 3C273 and consistent in position with the SIGMA source GRS1227+025. The EXITE2 spectrum is consistent with a power law with photon index 3 and large low energy absorption, as indicated by the GRANAT/SIGMA results. No source was detected in more sensitive followup EXITE2 observations in 2000 and 2001 with 3$\sigma$ upper limits of 190 and 65 mCrab, respectively. Comparison with the flux detected by SIGMA shows the source to be highly variable, suggesting it may be non-thermal and beamed and thus the first example of a ``type 2'' (absorbed) Blazar. Alternatively it might be (an unprecedented) very highly absorbed binary system undergoing accretion disk instability outbursts, possibly either a magnetic CV, or a black hole X-ray nova.

12 pages, 4 figures, accepted for publication in ApJ

References in corpus (5)

• Simultaneous observations of the quasar 3C 273 with INTEGRAL, XMM-Newton and RXTE
• RX J2217.9--5941: A highly X-ray variable Narrow-Line Seyfert1 galaxy
• Development of an XSPEC-Based Spectral Analysis System for the Coded-Aperture Hard X-ray Balloon Payload EXITE2
• Background Measurements from Balloon-Borne CZT Detectors
• Balloon Flight Background Measurement with Actively-Shielded Planar and Imaging CZT Detectors

Cited by in corpus (1)

• Astrophysics in 2005